Quote:
Originally Posted by ChazInMT
Hey Chills, there is an autospeed article out somewhere in which they visit a wind tunnel guy. I think the article may have some sorta Camaro getting its drag reduced. In the article the wind tunnel expert had a list of things that worked, and a list of things that didn't.
As for dimples, his quote was something to the effect that, "Unless your car is the shape of a 1 5/8" sphere, dimples will not do you any good."
Ironically I first showed up here 5 years ago with all sorts of lets dimple the car ideas, but it was a great starting point to begin exploring this aerodynamics world here.
Needless to say I have learned to just forget anything that seems like a fad after many far better educated minds than mine have said it's not a viable option.
This dimple thing is one those ideas you should just let it go.........
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I'm not coming here with lots of "lets dimple the car ideas"... I don't have answers, I don't claim to know what will or won't work, I just know that I'd like to learn more about this. So I posted the materials and hoped for some enlightening information for or against the materials the application or the science... There is a lot of science out there that supports dimples... The people that say it won't work, never provide any statistical or factual evidence to support their claim... They make statements like "is your car a sphere?" or "do you see planes with dimples" or "this one guy said it wouldn't work in an article". In 2009 Modeling of train cars (in an actual wind tunnel 1:20 models) showed potential for 20% reduction in skin friction at high speeds when dimples were used. Dimples also allowed air to more easily "jump" the gap between train cars which allows for a decrease in pressure drag as well.
"A parameter called dimple ratio (DR) was introduced. DR is the ratio between the depth of a half dimple over the print diameter of a dimple (Figure 4). In his work, a car model (Figure 5) was simulated with a DR of 0.05 - 0.5.
His Ahmed body car model is a simplified car model for accurate flow simulation, retaining its standard car features such as curved fore body, straight centre section and angled rear end. It is a typical bluff body commonly used for simulation to study the flow past of a car (Figure 4). Flow was simulated using k-ε turbulence model in ANSYS Fluent software with tetrahedral meshing (Figure 6).
For the model without dimple application, there is insignificant turbulent kinetic energy on the car surface (Figure 7). When compared to the model without a dimple, kinetic turbulent energy is generated within the dimple and at the vicinity of the dimple edge. These results suggest that the flows manage to go further before flow separation takes place.
The coefficient of drag, CD, is reduced by 1.9% for the model with DR = 0.4.
The results are encouraging since the simulation is only based on one dimple.
Different parameters like dimple position, number of dimples and dimple orientation will be tested in order to fully understand the performance of the dimple application on vehicle aerodynamics." (2013)
There isn't a lot of research out there to learn from, and what is out there, is incomplete in regards to actual application... I guess I'll just wait however long it takes for someone to finish testing
Thanks for your reply though, and I'll see if I can find that article!
~C